1. Field of the Invention
Umbrellas, intending to shade the sun such as beach umbrellas, picnic umbrellas and the like require a large radius to be effective. Consequently, conventional folding sun umbrellas have been overly large and have as a result a complex rib and bracing structure as is required to maintain the relatively heavy canvas or plastic fabric cover in taut extended position.
2. Description of the Related Art
Conventionally folding umbrellas comprise a fabric cover disposed over a plurality of ribs hinged at one end to a central rod extending spoke-like outwardly from the rod. Each rib is extended and held in open condition by an articulating triangular bracing arrangement comprising a strut secured at one end to a slide riding on the rod and hinged at its other end to the rib, medial of its ends. It should be thus apparent that the length of the rib is in direct proportion to the radius of the umbrella and consequently a large diameter sun umbrella requires long ribs.
As the ribs are increased in length, they must be made of stronger and of heavier material so as to be able to carry the correspondingly enlarged fabric cover. As a result, the ribs must be provided with a stronger and more complex bracing system, including additional struts and additional articulation points.
In my earlier U.S. Pat. Nos. 4,007,753 and 4,350,175 sectional, fold-over ribs were employed as are used in standard umbrellas. I have found that such ribs are not useful when large diameter umbrellas are required.
It is the object of the present invention to provide a folding umbrella, of large diameter, which overcomes the disadvantages and inconveniences of the prior art.
It is a further object to provide a sun umbrella of the folding type which is light in weight and simpler in construction than those heretofore known.
It is a further object of the present invention to provide an umbrella construction having an improved and simplified rib and bracing arrangement.
These objects as well as others together with the numerous advantages will be apparent from the following disclosure of the invention.